Cargo racks that attach to the rear of work vehicles are well known in the prior art. These devices are typically attached to create additional cargo space to carry such items as machines, tools, and other equipment. They can also be detached when not in use so as not to be an obstruction and to reduce any inconvenience to the driver.
Cargo racks in the prior art come in two general categories. The first type of cargo rack is suspended behind the vehicle by support bars, so that no part of the cargo rack is touching the ground. Examples of this type are shown in U.S. Pat. No. 4,915,276 to Devito, U.S. Pat. No. 5,033,662 to Godin and U.S. Pat. No. 5,427,289 to Ostor. The second type of cargo rack has wheels attached to its sides and is pulled behind the vehicle in a trailer-like fashion. Examples of this type are shown in U.S. Pat. No. 5,018,651 to Hull et al. and U.S. Pat. No. 5,368,209 to Hill.
The attachment used between the cargo rack and the vehicle depends on the type of cargo rack being used. For the suspended-type cargo rack, a strong and stable connection is required. Male and female connectors of the type shown in FIG. 1 of U.S. Pat. No. 4,744,590 to Chesney, exemplifies the type of connection commonly used.
For the trailer-type cargo rack, the connection must be able to rotate to allow the cargo rack the freedom to move independently behind the vehicle. A ball-joint connector is typically used for this purpose and is shown in FIG. 2 of Chesney.